Light emitting diode device

Abstract

A plurality of separate lead frames can be insert-molded in a reflector composed of a white resin having a high reflectivity to form a package for an LED device. A cavity is formed in the reflector. The cavity can have an inner circumferential surface that opens wider in an upward direction. Cups can be located in the cavity. Each cup has an outer wall that can be in the form of a cylinder with the bottom formed of each of two separate lead frames. A red LED chip and a green LED chip can be adhesively fixed to the lead frames located on the bottoms of the respective cups. The LED chips can have lower electrodes, which are electrically brought into conduction with the lead frames one by one. The LED chips can also have upper electrodes, which are electrically brought into conduction with the lead frames one by one via bonding wires. A light transmissive resin can be filled in the cavity.

Description

[0001] This application claims the priority benefit under 35 U.S.C. §119 of Japanese Patent Application No. 2004-277764 filed on Sep. 24, 2004, which is hereby incorporated in its entirety by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates to a light emitting diode (LED) device. More particularly, it relates to an LED device including LED chips of two or more types having different light source colors that are combined as light sources to provide a light of a desired tone by mixing the light emitted from the various LED chips. [0004] 2. Description of the Related Art [0005] A spectrum of light emitted from an LED chip has a sharp rise and fall, which provides a light source color of a tone approximately corresponding to a peak emission wavelength in a spectral distribution. An LED light source having such an optical property may be employed in a method to provide a light of a tone different from the light source color. In this met...

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Benefits of technology

[0033] Therefore, when the light reaches the convex lens, it exists within a narrow zone. Accordingly, relatively mild light condensation can efficiently condense the light to be externally emitted. Thus, even a convex lens having a small curvature is possible to sufficiently exert a light condensing effect and realize a low-height LED device.

[0034] As the distance between adjacent cups can be made shorter as compared to the related art, it is possible to downsize the LED device and contribute to downsizing the instrument that includes the LED device mounted thereon.

[0035] Similarly, as the distance between adjacent cups can be shortened, even if the LED chips having different light source colors are used to configure particular types of light sources, light emitted from the LED chips can be mixed well. This is advantageous to provide an LED device that has excellent color mixture characteristics.

[0036] The shape of the convex lens formed above the LED chip can be controlled to freely set the degree of condensing the light that is emitted from the exit surface of the lens. This means that the distribution of light emitted from the LED device can be freely controlled.

[0037] The outer wall defining the cup can be formed on molding, etc. Therefore, application of a process to the mold makes it possible to freely set the shape of the cup without any constraint. Accordingly, the flexibility in determining the light distribution by the shape of the cup is large, and the distribution of light that is emitted from the LED chip and which reaches the convex lens can be realized in an ideal form.

[0038] As a result, it is possible to realize an optimal light distribution in consideration of conditions and environments for the use of the LED device, such as the distance and direction associated with observation of the LED device and the shape and size of an object illuminated by the LED device.

Problems solved by technology

However, the above-described related art LED device can not typically be mounted on the same surface of a single-sided board on which surface-mount electronic components are mounted.

Accordingly, the height of the electronic components mounting board is increased and the cost of the printed wire board is elevated, which in turn elevates the cost of the electronic components mounting board and electronic instrument itself.

Therefore, the shortest distance between adjacent LED chips mounted on the cups is limited as determined by the thickness of the lead frame.

In such a case, when plural LED chips having different light source colors are mounted in respective cups to mix the light that is emitted from the LED chips, the LED chips may not be located sufficiently close to each other for a particular purpose or application.

As a result, the LED device may result in an insufficient light mixture and / or a deteriorated color mixture, etc.

A constraint on the interval between the cups also exerts an influence on the ability to downsize the LED device, often resulting in insufficient downsizing.

Therefore, the flexibility of the optical design associated with the LED device is limited, and the optically and structurally ideal best product can not be made.

It is difficult work to form the cup integrally with the circuit pattern composed of the flat metal plate such that it has an extremely narrow width.

In this case, elevation of the mold production cost due to the complicated press mold and insufficient dimension accuracy may invite elevation of the production cost and deterioration of quality.

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